Since a lens of a camera has distortion characteristics, a generated image contains distortion. Further, an effect, such as enlargement, reduction, rotation, and shearing, occurs depending on an installation condition of a capturing device, and generated image data further contains a difference from a real image. In addition, even when reproducing a recorded image, there is a possibility that the reproduced image has an effect, such as enlargement, reduction, rotation, and shearing, depending on an installation situation of a reproduction device. The image processing apparatus that corrects such a difference between the real image and the generated image determines pixels of an uncorrected image necessary for generation of pixels of a corrected image, respectively, reads the determined pixels, and performs image processing.
In general, a storage device storing image data tends to be more expensive as the device has a higher processing speed. Accordingly, a low-speed storage device is used in order to store large image data corresponding to one frame at low cost. In this case, the processing speed is lowered in the above-described image correction processing of repeatedly reading the same image data.
An example of the background art in this technical field is JP 2011-211274 A (PTL 1). This publication describes that “an image display device includes a frame image storage unit, a block image storage unit that has a plurality of block regions and stores block image data, a correction processing unit that generates corrected pixel data using the block image data, a display unit that displays the corrected frame image, a determination unit that issues an acquisition request for acquiring the block image data to be used for generation of first corrected pixel data, a block image prediction unit that issues an acquisition request for acquiring the block image data to be used for generation of second corrected pixel data generated after the first corrected pixel data, and a block image acquisition unit that acquires block image data designated in preference to the acquisition request issued by the block image prediction unit when the acquisition request is issued by the determination unit” (see Abstract).